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Title: OFDM Relaying System with Subcarrier Pairing:
Other Titles: Performance of Multicarrier communications in fading channels Subject: Wireless Communications
Authors: Ali Shah, Raza
Issue Date: 2017
Publisher: Higher Education Commission – Pakistan
Abstract: In this monograph, the OFDM relaying system with subcarrier pairing is analyzed in various fading conditions. The most common urban fading channel models, i.e., Rayleigh and Nakagami-m are selected for performance analysis. The bit-error rate (BER), ergodic capacity, outage probability and outage capacity performances of the system are compared with ordered subcarrier pairing (OSP) schemes, i.e., best-to-best (BTB) pairing, well known for capacity-enhancement and worst-to-best (WTB) pairing, well known for BER minimization. The BER performance of OFDM relaying system is analyzed in a multipath Nakagami- m fading channel. It is verified through analytical and numerical proofs that the parameter m translates to the new fading severity parameter m0 in case of two-hop OFDM relaying system and the range 1 2 m < 1 corresponds to 1 2 < m0 < 2 for large number of resolvable channel paths L. For multipath Nakagami-m fading channel model between source-to-relay (S-R) and relay-to-destination (R-D) links, closed-form expressions are derived for the probability density function (PDF) and moment generating function (MGF) of end-to-end SNR for integer as well as non-integer values of m, hence, m0. The classical PDF and MGF based approaches are used for the comparison of systemperformance with WTB pairing and BTB pairing schemes on the basis of BER. The effect of m and L on the BER variations is thoroughly investigated. The ergodic capacity performance of two-hop OFDM relaying system for OSP schemes is then examined. Jensen’s inequality is solved to derive the close-form expressions for ergodic capacity. The performance analysis on the basis of system’s ergodic capacity is then described. Outage capacity, which is more flexible and realistic capacity measure, and considers higher moments of end-to-end SNR, is then analyzed. Closed-form expressions for the outage capacity of the system with WTB pairing and BTB pairing are derived for Rayleigh as well as Nakagami-m fading multipath channels for each hop. Two special cases of Nakagami-m fading, i.e., one side Gaussian fading 􀀀 m = 1 2 and Rayleigh fading (m = 1) are, specifically, focused. The outage probability, which is an important performance metric, is then analyzed. Closed-form expressions are derived for the outage probability of the system in terms of CDF and PDF of end-to-end SNR of hop-1 and hop-2 respectively. The performance of the system with OSP schemes is compared for a wide range of SNR in multipath Rayleigh as well as Nakagami-m fading channels. The effect of m and L on the variations of outage probability is thoroughly investigated. Various analytical proofs with illustrations are presented to show the accuracy and validity of our derived expressions. The proximity of theoretical and numerical results validates our work and compares the performance of two-hop OFDM relay system with OSP schemes for various performance measuring parameters. The analysis is extended for OSTB-OFDM relaying system to model more practical scenarios and system equations are developed. Multiple transmit antennas with AF relaying is assumed for system investigation. The results are obtained by applying maximum likelihood detector (ML) at the receiver.
ISBN: 978-969-417-NIL-1
Appears in Collections:Monographs.

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